Table Notes:

* Independent city, not politically incorporated within a county.** County became part of metropolitan area in 1950.(p) Part of county.

# Area-Specific Notes:

Baltimore, MD Baltimore became an independent Cityin the 1850s.

Bergen/Passaic, NJ In 1970, Bergen and Passiac counties were included in the Paterson/Clifton, NJ metro area. Passaic County remained in the Paterson/Clifton metro in 1980 but Bergen County was defined as part of the New York metro area. In 1990, the two counties were defined as their own metro area.

Boston, MA The 1940 and 1950 samples use New England County Metropolitan Areas. All other samples use towns and cities rather than counties.

Boulder, CO Boulder was included in the Denver metro area in 1970 and 1980 but was a separate Primary Metro in 1990.

Chicago, IL Gary-Hammond, IN is designated as a separate metropolitan area in 1970.

Denver, CO In 1900 Denver was a part of Arapahoe County but annexed territory from that county and became independent by 1910. The only area meeting the criteria for metropolitan status in 1910 and 1920 was the Cityof Denver. Boulder was included in the Denver metropolitan area in 1970 and 1980 but was made a separate Primary Metro in 1990.

Gary-Hammond, IN See Chicago, above.

Greensboro-Winston Salem-Highpoint, NC Winston-Salem and Greensboro are separate metropolitan areas from 1930 to 1950 and were combined from 1970 to 1990.

Los Angeles, CA San Bernardino was included in Los Angeles in 1930 but became an independent metropolitan area from 1930 through 1990.

New York, NY The New York metropolitan area has substantial rearrangement of counties due to the splitting of the area into smaller Primary Metros. This causes some counties, such as Bergen, to move among multiple metro areas over the last forty years (see Bergen/Passaic, above).

Norfolk-Virginia Beach-Newport News, VA Norfolk and Portsmouth had become independent cities by 1900 and South Norfolk by 1930.

Paterson/Clifton, NJ In 1970, Bergen and Passiac counties were included in the Paterson/Clifton, NJ metro area. Passaic County remained in the Paterson/Clifton metro in 1980 but Bergen County was defined as part of the New York metro area. In 1990, the two counties were defined as their own metro area.

Richmond, VA The independent Cityof Manchester is included in the Richmond metropolitan area in 1900 and 1910. Richmond annexed Manchester between 1900 and 1910. Since Richmond also annexed part of Henrico County, the unannexed remainder of Henrico County failed to meet the criteria for inclusion in the metro area in 1920.

Riverside-San Bernardino, CA See Los Angeles, above.

St. Louis, MO The Cityof St. Louis was an independent Cityby 1880.

Salt Lake City, UT Ogden, UT, was a separate metropolitan area in 1940 and 1950 but was combined with Salt Lake City in 1980.

San Francisco, CA Alameda and Contra Costa counties were split from the San Francisco metropolitan area in 1990 and became the Oakland metropolitan area. Solano County was part of the San Francisco metro area in 1940 and 1950, failed to meet metro criteria in 1960, but emerged as the separate metro area of Vallejo from 1970 to 1990.

Springfield, OH Springfield was a separate metropolitan area from 1920 to 1980 but was included in the Dayton metropolitan area in 1990.

Vallejo, CA See San Francisco, above.

Washington, DC Alexandria was an independent Cityby 1900. Arlington County changed its name from Alexandria County between 1910 and 1920.